The state of the art in vibration-based damage detection and health and usage monitoring is reviewed. The damage detection concepts and the signal analysis techniques are examined, explained, and compared. Latest advances in signal processing methodologies that are of relevance to vibration based damage detection (e.g., Wavelet Transform and Wigner-Ville distribution) are highlighted. These vib...

This research investigates a passive wireless antenna sensor designed for strain and crack sensing. When the antenna experiences deformation, antenna shape changes, causing shift in electromagnetic resonance frequency of the antenna. A radio frequency identification (RFID) chip is adopted for antenna signal modulation, so that a wireless reader can easily distinguish backscattered sensor signal...

A novel method for preparing and testing bending specimens in-situ the TEM has been developed. This method provides high visibility of the crack front and its associated plastic zone. This is significant because energy release rates can now be calculated at many points throughout the test based on crack tip opening displacement (CTOD), crack opening angle (COA), and crack advance. Further refin...

In this work, the plastic deformation mechanisms responsible for mechanical properties and fracture toughness in nanotwinned (NT) magnesium is studied by molecular dynamics (MD) simulation. The influence of twin boundary (TBs) spacing and crack position on deformation behaviors are investigated. The microstructure evolution at the crack tip are not exactly the same for the left edge crack (LEC)...

Damage detection and calibration in beams by wavelet analysis involve some key factors such as the damage model, the choice of the wavelet function, the effects of windowing and the effects of masking due to the presence of noise during measurement. A numerical study has been performed in this paper addressing these issues for single and multispan beams with an open crack. The first natural mod...

Microstructural degradation is a predominant source of damage in polycrystalline alloys that are commonly used in diverse applications. For early diagnosis and prognosis of failures, it is essential to understand the mechanisms of damage growth specifically in the crack initiation phase, which is still an intriguing phenomenon for scientists due to sensing inaccuracies and modeling uncertaintie...

modelling of crack propagation by finite element method under mixed mode conditions is of prime importance in fracture mechanics. this paper describes an application of finite element method to the analysis of mixed mode crack growth in linear elastic fracture mechanics. crack growth process is simulated by an incremental crack-extension analysis based on the maximum principal stress criterion,...

OBJECTIVES HIV prevalence among people who inject drugs (PWID) in Ottawa is estimated at about 10%. The successful integration of peers into outreach efforts and wider access to HIV point-of-care testing (POCT) create opportunities to explore the role of peers in providing HIV testing. The PROUD study, in partnership with Ottawa Public Health (OPH), sought to develop a model for community-based...